1. Field of the Invention
This invention is related to the field of processors and computer systems including processors, and to managing power consumption in such systems.
2. Description of the Related Art
Various types of mobile computing devices have become very popular, permitting users to do useful work at various locations remote from their fixed computing stations. Mobile computing devices include portable computers (also referred to as laptops), personal digital assistants (PDAs) such as those based on the Palm operating system (e.g. the Palm Pilot family of devices) as well as those based on the Windows CE platform, mobile communications devices such as the Blackberry line of products from Research in Motion, which provide wireless email access, and various wireless telephony devices such as cell phones, combinations of PDAs or Blackberries and cell phones, etc.
A common issue for all mobile computing devices is battery life. The longer the battery (or a given charge of the battery) can be made to last, the more satisfied the user is with the product and thus the more likely the user is to purchase their next product from the same manufacturer. Many mobile computing devices, especially laptops, may also be connected to an external power source (e.g. an A/C wall outlet) in addition to having an internal battery power source. When using an external power source, the battery is not used (and may in fact be charged from the external power source). Thus, higher power consumption may be permissible when using the external power source. Numerous power saving features have been implemented in various computing devices (e.g. the Advanced Configuration and Power Interface (ACPI) is frequently used in laptops). However, striving for improved battery life when the mobile computing device is not connected to an external power source is still an area of high interest and continuing innovation.